Cache code size/hash in storage (#893)

* cache code size/hash in storage

* use in-memory code

* don't clone metadata

* bump evm

* don't cache empty code metadata + tests

* clippy

* remove deprecated getter attribute

* remove dep on sha3 crate

* feedback

frame/evm/Cargo.toml

@@ -15,6 +15,7 @@ targets = ["x86_64-unknown-linux-gnu"]
 environmental = { workspace = true, optional = true }
 evm = { workspace = true, features = ["with-codec"] }
 hex = { version = "0.4.3", default-features = false, features = ["alloc"] }
+hex-literal = { version = "0.3.4" }
 impl-trait-for-tuples = "0.2.2"
 log = { workspace = true }
 rlp = { workspace = true }

frame/evm/src/lib.rs

@@ -76,7 +76,8 @@ use frame_support::{
 };
 use frame_system::RawOrigin;
 use impl_trait_for_tuples::impl_for_tuples;
-use sp_core::{Hasher, H160, H256, U256};
+use scale_info::TypeInfo;
+use sp_core::{Decode, Encode, Hasher, H160, H256, U256};
 use sp_runtime::{
 	traits::{BadOrigin, Saturating, UniqueSaturatedInto, Zero},
 	AccountId32, DispatchErrorWithPostInfo,
@@ -512,6 +513,10 @@ pub mod pallet {
 	#[pallet::storage]
 	pub type AccountCodes<T: Config> = StorageMap<_, Blake2_128Concat, H160, Vec<u8>, ValueQuery>;
 
+	#[pallet::storage]
+	pub type AccountCodesMetadata<T: Config> =
+		StorageMap<_, Blake2_128Concat, H160, CodeMetadata, OptionQuery>;
+
 	#[pallet::storage]
 	pub type AccountStorages<T: Config> =
 		StorageDoubleMap<_, Blake2_128Concat, H160, Blake2_128Concat, H256, H256, ValueQuery>;
@@ -525,6 +530,21 @@ pub type BalanceOf<T> =
 type NegativeImbalanceOf<C, T> =
 	<C as Currency<<T as frame_system::Config>::AccountId>>::NegativeImbalance;
 
+#[derive(Debug, Clone, Copy, Eq, PartialEq, Encode, Decode, TypeInfo)]
+pub struct CodeMetadata {
+	pub size: u64,
+	pub hash: H256,
+}
+
+impl CodeMetadata {
+	fn from_code(code: &[u8]) -> Self {
+		let size = code.len() as u64;
+		let hash = H256::from(sp_io::hashing::keccak_256(code));
+
+		Self { size, hash }
+	}
+}
+
 pub trait EnsureAddressOrigin<OuterOrigin> {
 	/// Success return type.
 	type Success;
@@ -720,6 +740,7 @@ impl<T: Config> Pallet<T> {
 		}
 
 		<AccountCodes<T>>::remove(address);
+		<AccountCodesMetadata<T>>::remove(address);
 		#[allow(deprecated)]
 		let _ = <AccountStorages<T>>::remove_prefix(address, None);
 	}
@@ -735,9 +756,40 @@ impl<T: Config> Pallet<T> {
 			let _ = frame_system::Pallet::<T>::inc_sufficients(&account_id);
 		}
 
+		// Update metadata.
+		let meta = CodeMetadata::from_code(&code);
+		<AccountCodesMetadata<T>>::insert(address, meta);
+
 		<AccountCodes<T>>::insert(address, code);
 	}
 
+	/// Get the account metadata (hash and size) from storage if it exists,
+	/// or compute it from code and store it if it doesn't exist.
+	pub fn account_code_metadata(address: H160) -> CodeMetadata {
+		if let Some(meta) = <AccountCodesMetadata<T>>::get(address) {
+			return meta;
+		}
+
+		let code = <AccountCodes<T>>::get(address);
+
+		// If code is empty we return precomputed hash for empty code.
+		// We don't store it as this address could get code deployed in the future.
+		if code.is_empty() {
+			const EMPTY_CODE_HASH: [u8; 32] = hex_literal::hex!(
+				"c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470"
+			);
+			return CodeMetadata {
+				size: 0,
+				hash: EMPTY_CODE_HASH.into(),
+			};
+		}
+
+		let meta = CodeMetadata::from_code(&code);
+
+		<AccountCodesMetadata<T>>::insert(address, meta);
+		meta
+	}
+
 	/// Get the account basic in EVM format.
 	pub fn account_basic(address: &H160) -> (Account, frame_support::weights::Weight) {
 		let account_id = T::AddressMapping::into_account_id(*address);

frame/evm/src/runner/stack.rs

@@ -854,6 +854,14 @@ where
 		self.substate
 			.recursive_is_cold(&|a: &Accessed| a.accessed_storage.contains(&(address, key)))
 	}
+
+	fn code_size(&self, address: H160) -> U256 {
+		U256::from(<Pallet<T>>::account_code_metadata(address).size)
+	}
+
+	fn code_hash(&self, address: H160) -> H256 {
+		<Pallet<T>>::account_code_metadata(address).hash
+	}
 }
 
 #[cfg(feature = "forbid-evm-reentrancy")]

frame/evm/src/tests.rs

@@ -651,3 +651,40 @@ fn eip3607_transaction_from_precompile() {
 		.is_ok());
 	});
 }
+
+#[test]
+fn metadata_code_gets_cached() {
+	new_test_ext().execute_with(|| {
+		let address = H160::repeat_byte(0xaa);
+
+		crate::Pallet::<Test>::create_account(address, b"Exemple".to_vec());
+
+		let metadata = crate::Pallet::<Test>::account_code_metadata(address);
+		assert_eq!(metadata.size, 7);
+		assert_eq!(
+			metadata.hash,
+			hex_literal::hex!("e8396a990fe08f2402e64a00647e41dadf360ba078a59ba79f55e876e67ed4bc")
+				.into()
+		);
+
+		let metadata2 = <AccountCodesMetadata<Test>>::get(&address).expect("to have metadata set");
+		assert_eq!(metadata, metadata2);
+	});
+}
+
+#[test]
+fn metadata_empty_dont_code_gets_cached() {
+	new_test_ext().execute_with(|| {
+		let address = H160::repeat_byte(0xaa);
+
+		let metadata = crate::Pallet::<Test>::account_code_metadata(address);
+		assert_eq!(metadata.size, 0);
+		assert_eq!(
+			metadata.hash,
+			hex_literal::hex!("c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470")
+				.into()
+		);
+
+		assert!(<AccountCodesMetadata<Test>>::get(&address).is_none());
+	});
+}